Fuel injection pump



March 29, 1960 E. s. DAHL E 2,930,320

FUEL INJECTION PUMP Filed Jan. 20, 1953 fnz/eni ar Zzlrzar .5. .Dcz/LZ mMzIZZz'am Newian FUEL INJECTION PUMP Einar S. Dahl, Decatur, Ill., andWilliam Newton, Dayton, Ohio, assignors to Borg-Warner Corporation,Clucago, 111., a corporation of Illinois Application January 20, 1958,Serial No. 709,846

2 Claims. (Cl. 103-2) of Einar S. Dahl, Serial No. 702,389, filedDecember It is an object of the present invention to provide an improvedfuel injection pump for direct cylinder injection, having an output thatvaries directly with the speed at which said pump is driven.

It is another object of the present invention to provide an improved.fuel injection pump having a rotatable and reciprocating plungerconnected to and driven by a rotatable cam for distributing fuel torespective cylinders of an internal combustion engine.

It is another object to provide a fuel injection pump in accordance withthe preceding object, wherein the cam is in contact with a plurality ofrollers and said plunger has a flexible connection with said cam forthereby allowing equal distribution of the driving load of the plungerupon the rollers.

It is an additional object to provide a fuel injection pump inaccordance with the preceding objects having means for lubricating therollers by the same liquid fuel as is delivered by the pump.

It is still another object to provide an improved cam and plunger for afuel injection pump withthe plunger having a partially rounded andpartially flatend in contact with said cam.

The invention consists of the novel constructions, ar-

rangements and devices to be hereinafter described and claimed forcarrying out the above stated objects and such other objects as willappear from the following description of a preferred form of theinvention, illustrated with reference to the accompanying drawings,wherein:

Fig. 1 is a longitudinal'sectional view of the improved pump of thepresent invention;

Figs. 2 and 3 are views taken on lines 2 -2 and 3'-3 of Fig.1; and

Fig. 4 is an enlarged fragmentary sectional view of a plunger and camutilized in the pump of Fig. 1.

Referring now to Fig. l, the improved pump of the present invention,designated by the numeral 10, comprises a driving section 11, and apumping section 12. The driving section 11 comprises a casing 13, adrive shaft 14 journalled within the casing 13, and a cam 15. The driveshaft 14 is driven by a rotatable part of an internal combustion engine(not shown) and rotatably drives the cam 15. A plurality of rollers 16are rotatably disposed within the casing.13 with their axes of rotationat right angles to the axis of the drive shaft 14 and are in contactwith a cam surface 17 of the cam 15.

.The pumping section 12 generally comprises an outer pump body 18, aninner pump body 19 slidably disposed within the outer body 18, and aplunger 20 reciprocatively and rotatably disposed within an axialcentral bore 21 formed in the inner body 19. The outer pump body 18 isattached to the casing 13 by a plurality of machine United States Patentpump body 19. A fluid tight seal also is provided between the outer pumpbody' 18 and the casing 13 by means of an O-ring 29 which is containedin an annular groove 30 formed in the casing 13.

The plunger 20 is formed with an enlarged cylindrical head 31 whichextends into acylindrical recess 32 formed in the cam 15. Thecylindrical head 31 is formed with a slot 33, and a driving connectionwith the shaft 14 is provided by means of a tang 34 formed integrallywith the shaft 14 which extends through the cam 15 and fits into theslot 33. The head 31 of the plunger 20 is formed with a partiallyrounded surface 35 and a partially fiat surface 36 in contact with anannular surface 37 in th bottom of the recess 32. Q

A spring retaining collar 38 encircles the plunger 20 and abuts againsta washer 39 which is disposed between the retaining collar 38 and theenlarged cylindrical head 31 of the plunger 20. A spring 40 is disposedunder con-,

stant compression between the retaining cap 38 and an annular portion 41of the inner pump body 19. The spring 40 tends to force the plunger 20and cam 15to the right as shown in Fig. 1 and press the cam surface 17against the rollers 16.

The inner pump body 19 is formed with a pluralityof fuel inlet ports 42,a fuel spill port 43 and a plurality of fuel delivery ports 44. Theplunger 20 is formed with an axial central cavity 45 which extendsthroughout approximately one half of the length of the plunger 20. Theplunger 20 also is formed with a plurality of fuel inlet ports 46 and afuel delivery port 47. 'The ports 46 extend radially outward from thecentral cavity 45 and are adapted to be aligned with the fuel inletports 42 of the pump body 19 as the plunger 20 rotates. The fueldelivery port 47 also extends radially outward from the central cavity45 and is adapted to be aligned with the fuel delivery ports 44 as theplunger 20 rotates. An end 48 of the plunger 20 is adjacent to the spillport 43 and restricts the port 43 as the plunger 20 reciprocates'.

The pump 10 is adapted to be lubricated by a portion of the same liquidfuel as is pumped by the plunger 20.

. through channels 53 formed in the casing 13. Each channel '53communicates with the cavity 51 and with a chamber 54 formed in thecasing 13 at the radially outward end of each shaft 52- Fuel is allowedto pass from the chamber '54 through a central opening 55 in each shaft52 to a radially extending port 56 also formed in the-shaft 52. Fuelpassing through the central opening 55 and the port 56 lubricates theinterior of the roller 16.

Lubrication of the plunger '20 also is providedby means or an annulargroove '57 formed on the plunger- 20. 1A port 58 is in communicationwith the groove 57 and'opens into the cavity 49 for allowing passage offuel to the groove 57.

Fuel discharged by the pump '10 is distributed in timed relationship toa plurality of nozzles 59 extending into the cylinders of an internalcombustion engine (not shown). Each of the nozzles 59 is connected witha delivery port 44 through a fluid conduit 60.

In operation, the pump functions as follows: the drive shaft 14 isdrivenby a rotatable part of the internal combustion engine (not shown),and rotatably drives the plunger 20 and cam 15. The cam surface 17 incontact with the rollers 16 imparts a reciprocating motion to theplunger 20 as it rotates. During the intake stroke of the plunger 20,that is, when the plunger is moving to the right as shown, the inletports 46 become aligned with the inlet ports 42 in the pump body 19.Fuel is drawn into the cavity 45, and as the plunger 20 rotates stillfurther, communication with the inlet ports 42 is cut off. During thedelivery stroke of the plunger 20, that is, to the left as shown in Fig.1, the fuel within the cavity 45 and the central bore 21 is compressedby the plunger 20. A portion of the fuel within the bore 21 isdischarged past the end 48 of the plunger 20 through the spill port 43.As the plunger 20 moves further to the left, the spill port 43 is cutoff and the fuel delivery port 47 in the plunger 20 becomes aligned withone of the delivery ports 44. Fuel is discharged through the deliveryports 47 and 44, the conduit 60, and the nozzle 59 into a cylinder ofthe internal combustion engine. As the plunger rotates still further,communication between the ports 47 and 44 is cut off and the inlet ports46 again become aligned with the inlet ports 42. The cycle justdescribed is repeated for as many fuel delivery ports and as manycylinders as there are in the internal combustion engine.

The quantity of fuel delivered through each of the delivery ports 44 isdetermined by the proportion of fuel discharged through the spill port43. The proportion of fuel delivered to that spilled can be varied byturning the cap nut 23. Turning of the cap nut causes the inner pumpbody 19 and the spill port 43 to be moved axially with respect to theend 48 of the plunger 20. The proportion delivered to the nozzles 59thus can be increased or decreased depending upon the direction ofrotation of the cap nut 23.

Fuel existing within the cavity '49 is allowed to pass through the port51a and into the cavity 51. Fuel present' within the cavity 51 acts as alubricant between the rollers 16 and the cam surface 17. A portion ofthe fuel within the cavity 51 can pass through the channels 53, thechambers 54, the central openings 55 and the port 56 for lubricating theinterior of each of the rollers 16.

The flexible connection provided between the cam and the head 31 of theplunger functions to equalize the driving load of the plunger 20 uponeach of the rollers 16, as will now be described. It is virtuallyimpossible to so locate the shafts 52 in the casing 13 that the cam 15would maintain uniform contact with the rollers 16 if the cam 15 wereformed integral with the plunger 20. at all times with all three of therollers 16 shown. The driving force for reciprocating the plunger 20 istransmitted through the contacting surfaces 36 and 37. The partiallyrounded surface formed on the head 31 allows the cam 15 to tilt slightlyand still maintain a driving connection with the head 31 forreciprocating the plunger 20. Where provision is made, as in the presentinvention, for equalizing the load on the rollers 16, the lubricationrequirements of each of the rollers 16 can be satisfied by the liquidfuel. The liquid fuel has sufiicient lubricating qualities for thispurpose. If the driving load were not equally distributed between therollers 16, the roller or rollers carrying the greater load wouldrequire additional lubrication and it would be necessary to provideauxiliary lubricating means for the driving section 11 of the pump 10.

The cam 15 should maintain equal contact a There has been provided bythis invention an improved fuel, injection pump having an output thatvaries directly with the speed at which the pump is driven. The pump hasa rotating and reciprocating plunger driven by a rotating cam in contactwith a plurality of rollers, and the driving load of the plunger isequally distributed over the various rollers, thereby permittinglubrication of the rollers by the same liquid fuel as is delivered bythe pump.

It is to be understood that the invention is not to be limited to thespecific constructions and arrangements shown and described, except onlyinsofar as the claims may be so limited, as it will be apparent to thoseskilled in the art that changes may be made without departing from theprinciples of the invention.

We claim:

1. In a fuel injection pump for supplying liquid fuel to an internalcombustion engine, the combination of a casing having a cylindrical boretherein, a plunger disposed within said bore, and drive means forrotating and reciprocating said plunger, said drive means including adrive shaft, a plurality of rollers rotatably mounted in said casing anda rotatable cam disposed axially between said rollers and said plungerfor reciprocating said plunger as said cam and said plunger rotate, andspring means for forcing and maintaining said plunger in contact withsaid cam, said plunger being formed with a cylindrical head having adriving connection with said drive shaft including a slot for rotatingsaid plunger and a partially round and partially flat end surface incontact with said cam for reciprocating said plunger, whereby said camis allowed to tilt slightly with respect to said plunger and therebymaintain equal contact with each of said rollers.

2. In a fuel injection pump for supplying liquid fuel to an internalcombustion engine, the combination of a casing having a cylindrical boreand a fuel supply chamber therein; a fuel delivery plunger having acylindrical driving head and disposed within said bore; and drive meansfor rotating and reciprocating said plunger, said drive means includinga drive shaft, a rotatable cam formed with a cylindrical recess forreceiving and retaining the head of said plunger and having a drivingconnection therewith and a plurality of rollers rotatably mounted insaid casing and in contact with said cam for imparting a reciprocatingmotion to said plunger as said cam rotates and spring means formaintaining the head in contact with said cam, said plunger head beingformed with a slot forming a driving connection with said drive shaftfor rotating said plunger and a partially flat end surface in contactwith a fiat surface on said cam and said plunger head also being formedwith a partially round surface surrounding and adjacent to said flatsurface for thereby providing a flexible driving connection with saidcam for reciprocating said plunger, whereby said cam is allowed to tiltslightly with respect to said plunger as said cam rotates and therebymaintain equal contact with each of said rollers.

References Cited in the file of this patent UNITED STATES PATENTS2,478,528 Edwards Aug. 9, 1949 2,567,367 Deschamps Sept. 11, 19512,582,535 Drouot Jan. 15, 1952 2,667,840 High Feb. 2, 1954 2,759,422Miller Aug, 21, 1956 2,810,376 Aldinger Oct. 22, 1957 FOREIGN PATENTS1,070,407 France Feb. 24, 1954

